The claimants sought judicial review of a decision of the Minister for the Civil Service (the Prime Minister) to ban trade union membership at a defence establishment on national security grounds.

A legitimate expectation may arise based on consistent past practice.

The House of Lords had to decide whether a statement made by the Secretary of State revoking immigration controls in 2000 created a legitimate expectation that the Chagos Islanders would be allowed to return and settle permanently on the outer islands.

Legitimate expectation has to be based on a promise which is both clear and unambiguous.

C was severely disabled. In 1993, she and number of other disabled patients were moved from hospital to Mardon House. The Health Authority (HA) had promised that this would be their home for life. The HA decided to close Mardon House and transfer C to the local authority for long-term nursing care.

If a public body exercising a statutory function makes a promise as to how it will behave in the future which induces a legitimate expectation of a benefit which is substantive, rather than merely procedural, to frustrate that expectation can be so unfair that it will amount to an abuse of power. In such circumstances, the court had to determine whether there was a sufficient overriding interest to justify a departure from what had previously been promised.

This case concerned a group of prisoners sentenced to mandatory terms of life imprisonment. The actual sentence is divided between a penal component, consisting of the period that the trial judge considers necessary, and an additional risk component, which is the period after the penal element has been served that is considered necessary before the risk to the public is sufficiently reduced to justify release. This is decided by the Home Office. The trial judge will make a recommendation (which does not have to be followed) after which the Home Secretary and senior officials at the Home Office exercise a wide discretion. Mandatory lifers were not informed about the tariff or told of the original judicial recommendation, nor were they made aware whether the Home Office had departed from the sentence that had been set by the trial judge.

The principles of fairness are not to be applied by rote identically in every situation. What fairness demands is dependent on the context of the decision. Lord Mustill went on to say that the giving of reasons may be inconvenient, but he could see no ground at all why it should be against the public interest.

The House of Lords had to decide whether or not to modify the rules regarding the test for bias.

When considering bias the court will ascertain all the circumstances which have a bearing on the suggestion that the judge was biased and ask whether those circumstances would lead a fair-minded and informed observer to conclude that there was a real possibility or a real danger that the tribunal was biased. There is no difference in meaning between real possibility and real danger.

Under s 191 Municipal Corporations Act 1882 the watch committee had power to ‘at any time suspend and dismiss any borough constable whom they think is negligent in the discharge of his duty or otherwise unfit for the same’. The appellant was dismissed by the committee. No specific charge had been formulated against him. He sought a declaration from the court that his dismissal was illegal and ultra vires.

The claimant had the right to a hearing before an unbiased tribunal, the right to know the accusations made against him, and the opportunity to answer those allegations.